What is the XMP file?

[flaclick]

Hi Everyone,
I transferred about 1,000 CR2 files from my card to my PC. I renamed all the images. This is the first time I have decided to rename my images. And this is the first time I ever noticed a small file, .XMP, with each image. Is the xmp file a result of my renaming? And do I need to keep them? If I delete them, am I loosing my exif data?

Thanks in advance,

Ruth

[*Mike*]

.XMP files are called sidecar files. Photoshop (or the like) creates them when working with RAW files. RAW files themselves are never altered - so all changes are written to this sidecar file. An alternative (with pros and cons) is for the changes to be recorded in a centralized database - then you never see the nuts and buts...